Changes between Version 130 and Version 131 of WikiStart


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Timestamp:
Oct 2, 2016, 6:30:28 PM (4 years ago)
Author:
davarpan1s
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  • WikiStart

    v130 v131  
    121121Experiment name: fixstr1_1909a
    122122Filenames: fixstr1_1909a1, fixstr1_1909a2
    123 Location: Position 1 (75% of the way down the straight section, 58 cm upstream from the end of straight section). Input rate: 12 l/s, density excess: 20 kg/$m^3$. Water was very cloudy to the extent that we were not able to use the laser. No siphon rig was used. Running basal ADV with ADV !#1 located 7.2 cm from the base. ADV just measured at one point (no traverse measurement).
     123Location: Position X1 (75% of the way down the straight section, 58 cm upstream from the end of straight section). Input rate: 12 l/s, density excess: 20 kg/$m^3$. Water was very cloudy to the extent that we were not able to use the laser. No siphon rig was used. Running basal ADV with ADV !#1 located 7.2 cm from the base. ADV just measured at one point (no traverse measurement).
    124124
    125125Experiment started at 2:45pm and stopped at 3:15 pm. The flow automatically stopped part way through as a valve was not open for recirculating water. Part way through red dye was added to visualise the current. Dye visualisation suggested pretty thin flow on the inner bank and significant super elevation on the outer bank. Some perturbation was observed on the surface of the flow at the outer bank, but otherwise the flow surface appears quite smooth, and mixing appeared to be very low. Mean maximum flow velocity from raw output was around 20 - 25 cm/s. ADV and UVP measured twice, the first is referred to as fixstr1_1909a1 and this had a velocity range of 0.3 m/s on the ADV setting, and 0.25 m/s for the UVP. Instantaneous flow velocities were faster than anticipated, as a result of the steep slope (3.5 degrees) with flow wrapping on both instruments so the velocity range was increased on the ADV and the UVP. A second run period fixstr1_1909a2 had a velocity range of 0.5 m/s on the ADV setting. The UVP setting was 680 mm/s (0.68 m/s).
     
    144144'''Monday, September 26th 2016'''
    145145
    146 Experiment name: fixstr1_2609a,b.  Filenames: fixstr1_2609a, fixstr1_2609b. Location: Position 1 (75% down straight section, 58 cm upstream from the end of the straight section). Input rate 5.9 l/s. Density excess 19 kg/m3. Laser was not used in the experiments today. Running basal ADV with ADV !#1 located 7.2 cm, ADV !#2 located at 10 cm and ADV !#3 located at 12 cm above channel bed.
     146Experiment name: fixstr1_2609a,b. 
     147Filenames: fixstr1_2609a, fixstr1_2609b.
     148Location: Position X1 (75% down straight section, 58 cm upstream from the end of the straight section). Input rate 5.9 l/s. Density excess 19 kg/m3. Laser was not used in the experiments today. Running basal ADV with ADV !#1 located 7.2 cm, ADV !#2 located at 10 cm and ADV !#3 located at 12 cm above channel bed.
    147149
    148150fixstr1_2609a: The main goal was to investigate if the concentration of the gravity current, inlet box and tank D were equal (19 kg/m3). The traverse sent one TTL signal to the ADV and didn’t send a return signal so only one measurement at one point was made by the ADVs (all ADVs collected data simultaneously). On the middle ADV (!#2) wrapping occurred which indicates that velocity needs to be increased to 0.6 m/s. UVP files showed a fair amount of noise in the data which requires further investigation. We waited about 7:20 minutes for the flow rate to reach a constant value. One person took 6 samples (every 3 minutes, starting at t = 0) from the mixing tank on the third floor which contained the salt water mixture coming from tank D. A second person took 6 samples (every 3 minutes, starting at t = 0) from the inlet box at the upstream end of the channel. A third person took 3 sets of 12 siphon samples every 5 minutes (starting at t = 0, duration = 1 min).
     
    159161Density of siphon samples from Monday, Sept 26 were measured. Two large PVC tubes (dia ~ 40 cm) were placed in the inlet box and weighted down to reduce the volume (new vol ~ 150 L).
    160162
    161 Experiment name: fixstr1_2709a,b.  Filenames: fixstr1_2709a, fixstr1_2709b. Location: Position 1 (75% down straight section, 58 cm upstream from the end of the straight section). Input rate 6 l/s. Density excess 20 kg/m3. Laser was not used in the experiments today. Running basal ADV with ADV !#1 located 7.2 cm, ADV !#2 located at 10 cm and ADV !#3 located at 12 cm above channel bed.
     163Experiment name: fixstr1_2709a,b. 
     164Filenames: fixstr1_2709a, fixstr1_2709b.
     165Location: Position X1 (75% down straight section, 58 cm upstream from the end of the straight section). Input rate 6 l/s. Density excess 20 kg/m3. Laser was not used in the experiments today. Running basal ADV with ADV !#1 located 7.2 cm, ADV !#2 located at 10 cm and ADV !#3 located at 12 cm above channel bed.
    162166
    163167Fixstr1_2709a: The goal was to examine the flushing time of the inlet box to see how it behaves once the PVC tubes were installed. One conductivity probe (C1T1) was mounted at the centerline just before the flow straightener (metallic honeycomb). Started with 6 l/s and waited for 5 min to see how inlet box, UVP and pump behaved. The UVP and siphon pump were turned on to fix the suspected pulse that the pump imparted to the UVP. This did not resolve the SNR issue. The inlet box took a long time to reach a steady conductivity value. It was suggested to start with a higher flow rate and then reduce the flow rate to 6 l/s. The ADV and UVP data were still noisy. No siphon sampling was done.
     
    167171'''Wednesday, September 28th 2016'''
    168172
    169 Experiment name: fixstr1_2809a,b, c, d.  Filenames: fixstr1_2709a, fixstr1_2709b, fixstr1_2709c, fixstr1_2709d. Location: Position 1 (75% down straight section, 58 cm upstream from the end of the straight section). Input rate 20 l/s (initial ~ 2 minutes of each run) then reduced to 6 l/s. Density excess 18.4 kg/$m^3$. Laser was not used in the experiments today. Running basal ADV with ADV !#1 located 7.2 cm, ADV !#2 located at 10 cm and ADV !#3 located at 12 cm above channel bed.
     173Experiment name: fixstr1_2809a and fixapex2_2809b, c, d. 
     174Filenames: fixstr1_2809a, fixapex2_2809b, fixapex2_2809c, fixapex_2809d.
     175Location for fixstr1_2809a: Position X1 (75% down straight section, 58 cm upstream from the end of the straight section). Location for fixapex2_2809b, c, d: Position 4 (at the centre of the second apex).  Input rate 20 l/s (initial ~ 2 minutes of each run) then reduced to 6 l/s. Density excess 18.4 kg/$m^3$. Laser was not used in the experiments today. Running basal ADV with ADV !#1 located 7.2 cm, ADV !#2 located at 10 cm and ADV !#3 located at 12 cm above channel bed.
    170176
    171177fixstr1_2809a: The goal is to increase the seeding and test the ADVs and UVP for less noise. A new stem ADV was mounted to reduce the noise. The UVP didn’t change in terms of noise issue, so the problem does not lie with the seeding density. Another suggestion was to move the UVP box back to the back bench to reduce interference from the electronics on the traverse. Minimal improvement was seen on the ADV profile. The seeding seems to be getting stuck in the inlet box behind the flow straightening baffles - this was visually observed by a buildup of foam in the inlet box.